Shot material and method of blasting

ABSTRACT

It is an object of the present invention to provide a blasting method and a shot material, which are very practical both in the cost and the treatment performance. (a) A shot material containing a styrene ion-exchange resin or a waste material caused therefrom, or/and a dried sludge-derived material, (b) a shot material containing a resin which is comprised of a resin containing a rubber component and a resin containing no rubber component, and (c) a shot material containing at least one component selected from the group consisting of an epoxy resin composition and inorganic filler, and a blasting method using the shot material.

RELATED APPLICATION DATA

This application is a divisional of U.S. patent application Ser. No.10/504,304, filed Aug. 11, 2004, the entirety of which is incorporatedherein by reference to the extent permitted by law, which is the Section371 National Stage of PCT/JP03/01433. This application claims thebenefit of priority to PCT International Application No. PCT/JP03/01433,filed Feb. 12, 2003 and Japanese Patent Application Nos. P2002-034607,filed Feb. 12, 2002, P2002-034611, filed Feb. 12, 2002, andP2002-096980, filed Mar. 29, 2002.

BACKGROUND OF THE INVENTION

The present invention relates to a shot material and a blasting methodusing the shot material.

Blast processing is used in a wide variety of fields for peeling acoating, such as a white line on the pavement, and removing otherdeposits, removing a deposit to a rubber mold, removing a deposit, suchas paint, pollutant, rust, or surface oxide, deburring of a resin shapedarticle, or surface abrasion. Conventionally, as a shot material for usein the blast processing, particles made of various materials, such asalumina, glass, or a resin, have been utilized. Recently, from theviewpoint of reduction and recycle of waste for preventing environmentalpollution, attempts are vigorously made to remove coating films inproducts disposed of (for example, metal materials and resin materialsin automobiles and household appliances) by blasting treatment using theshot material to reuse them as raw materials. Therefore, various studieshave been made on the shot material used in the blasting treatment(e.g., Japanese Patent Application Publication No. 2001-277123).

However, the blasting treatment for peeling the coating films in wasterequires a great amount of the shot material, and therefore posesproblems of costs for the material of the shot itself and for treatingthe used shot material. In addition, the shot material used for anobject of reusing waste becomes another waste and hence the used shotmaterial must be treated, antistatic properties must be imparted to theshot material for preventing it from adhering to the materials peeled,and safety must be secured for preventing an occurrence of dustexplosion, and these problems of treatments for the shot material arethe big hurdle that should be overcome for putting the shot materialinto practical use.

In view of the above problems accompanying the current techniques, anobject of the present invention is to provide a blasting method and ashot material, which are very practical both in the cost and thetreatment performance.

SUMMARY OF THE INVENTION

The present inventors have conducted extensive and intensive studieswith a view toward solving the above-mentioned problems. As a result, ithas been found that the use of, individually or in combination, (a) ashot material containing a styrene ion-exchange resin or a wastematerial caused therefrom, or/and a dried sludge-derived material, (b) ashot material containing a resin (C) which is comprised of a resin (A)containing a rubber component {heresinafter, frequently referred tosimply as “resin (A)”} and a resin (B) containing no rubber component{heresinafter, frequently referred to simply as “resin (B)”}, and (c) ashot material containing an epoxy resin composition and inorganic filleris extremely effective in solution or improvement of the above problems,and the present invention has been completed.

Specifically, the present invention is directed to:

(1) a shot material characterized in that it contains a styreneion-exchange resin or/and a dried sludge-derived material;

(2) the shot material according to item (1) above, characterized in thatthe styrene ion-exchange resin or/and the dried sludge-derived materialare contained in an amount of 0.1% by weight or more;

(3) the shot material according to item (1) above, characterized in thatthe styrene ion-exchange resin is a waste material which has been usedfor a purpose;

(4) the shot material according to item (1) above, characterized in thatthe dried sludge-derived material contains 30% by weight or more of aninorganic component;

(5) the shot material according to item (1) above, characterized in thatit further contains another shot material other than the styreneion-exchange resin and the dried sludge-derived material; and

(6) the shot material according to item (5) above, characterized in thatthe another shot material is at least one member selected from the groupconsisting of a thermosetting resin, a thermoplastic resin, abiodegradable polymer, a metal, a metal oxide, a metal hydroxide, ametal salt, ceramic, and carbon black.

Further, the present invention relates to:

(7) a blasting method characterized by using a shot material whichcontains a styrene ion-exchange resin or/and a dried sludge-derivedmaterial;

(8) the blasting method according to item (7) above, characterized inthat the styrene ion-exchange resin or/and the dried sludge-derivedmaterial are contained in an amount of 0.1% by weight or mores in theshot material;

(9) the blasting method according to item (7) above, characterized inthat the styrene ion-exchange resin is a waste material which has beenused for a purpose;

(10) the blasting method according to item (7) above, characterized inthat the dried sludge-derived material contains 30% by weight or more ofan inorganic component;

(11) the blasting method according to item (7) above, characterized inthat the shot material further contains another shot material other thanthe styrene ion-exchange resin and the dried sludge-derived material;and

(12) the blasting method according to item (11) above, characterized inthat the another shot material is at least one member selected from thegroup consisting of a thermosetting resin, a thermoplastic resin, abiodegradable polymer, a metal, a metal oxide, a metal hydroxide, ametal salt, ceramic, and carbon black.

Further, the present invention relates to:

(13) an industrial product having a surface treated with a shot materialwhich contains a styrene ion-exchange resin or/and a driedsludge-derived material;

(14) a method of reprocessing waste, characterized by conducting ablasting treatment using a shot material which contains a styreneion-exchange resin or/and a dried sludge-derived material; and

(15) a reproduced product obtained by a method of reprocessing wastecharacterized by conducting a blasting treatment using a shot materialwhich contains a styrene ion-exchange resin or/and a driedsludge-derived material.

Further, the present invention relates to:

(16) a blasting treatment method characterized by using a shot materialwhich contains a resin (C) comprised of a resin (A) containing a rubbercomponent and a resin (B) containing no rubber component;

(17) the blasting treatment method according to item (16) above,characterized in that at least one of the resin (A) containing a rubbercomponent and the resin (B) containing no rubber component is a usedresin;

(18) the blasting treatment method according to item (16) above,characterized in that the resin (C) is a used resin salvaged from a usedmagnetic recording product;

(19) the blasting method according to item (16) above, characterized inthat the weight ratio of the resin (B) containing no rubber component tothe resin (A) containing a rubber component {(B)/(A)} is in the range of0.001 to 5;

(20) the blasting method according to item (16) above, characterized inthat the content of the resin (C) in the shot material is 0.1 to 100% byweight; and

(21) the blasting method according to item (16) above, characterized inthat the resin (A) containing a rubber component is a HIPS (high impactpolystyrene) and/or ABS (acrylonitrile/butadiene/styrene resin), and theresin (B) containing no rubber component is a PS (polystyrene) and/or AS(acrylonitrile/styrene resin).

Further, the present invention relates to:

(22) a shot material which contains a resin (C) comprised of a resin (A)containing a rubber component and a resin (B) containing no rubbercomponent;

(23) the shot material according to item (22) above, characterized inthat at least one of the resin (A) containing a rubber component and theresin (B) containing no rubber component is a used resin;

(24) the shot material according to item (22) above, characterized inthat the resin (C) is a used resin salvaged from a used magneticrecording product;

(25) the shot material according to item (22) above, characterized inthat the weight ratio of the resin (B) containing no rubber component tothe resin (A) containing a rubber component {(B)/(A)} is in the range of0.001 to 5; and

(26) the shot material according to item (22) above, characterized inthat the content of the resin (C) in the shot material is 0.1 to 100% byweight.

Further, the present invention relates to:

(27) the shot material according to item (22) above, characterized inthat the resin (A) containing a rubber component is a HIPS (high impactpolystyrene) and/or ABS (acrylonitrile/butadiene/styrene resin), and theresin (B) containing no rubber component is a PS (polystyrene) and/or AS(acrylonitrile/styrene resin);

(28) an industrial product having a surface treated with a shot materialwhich contains a resin (C) comprised of a resin (A) containing a rubbercomponent and a resin (B) containing no rubber component;

(29) a method for reprocessing waste, characterized by conducting ablasting treatment using a shot material which contains a resin (C)comprised of a resin (A) containing a rubber component and a resin (B)containing no rubber component; and

(30) a reproduced product obtained by a method for reprocessing wastecharacterized by conducting a blasting treatment using a shot materialwhich contains a resin (C) comprised of a resin (A) containing a rubbercomponent and a resin (B) containing no rubber component.

Further, the present invention relates to:

(31) a shot material characterized in that it contains an epoxy resincomposition and inorganic filler;

(32) the shot material according to item (31) above, characterized inthat the epoxy resin composition and the inorganic filler are containedin an amount of 10% by weight or more;

(33) the shot material according to item (31) above, characterized inthat the inorganic filler is contained in an amount 1 to 20 times theweight of the epoxy resin;

(34) the shot material according to item (31) above, characterized inthat the epoxy resin composition is an epoxy resin composition for usein electric or electronic part;

(35) the shot material according to item (34) above, characterized inthat the epoxy resin composition is a discarded material produced in anencapsulation step for the electric or electronic part;

(36) the shot material according to item (34) above, characterized inthat the electric or electronic part is a semiconductor device; and

(37) the shot material according to item (31) above, characterized inthat the inorganic filler contains 70% by weight or more of a silicacomponent.

Further, the present invention relates to:

(38) a blasting method characterized by using a shot material whichcontains an epoxy resin composition and inorganic filler;

(39) the blasting method according to item (38) above, characterized inthat the shot material contains 10% by weight or more of the epoxy resincomposition and the inorganic filler;

(40) the blasting method according to item (38) above, characterized inthat the shot material contains the inorganic filler in an amount 1 to20 times the weight of the epoxy resin;

(41) the blasting method according to item (38) above, characterized inthat the epoxy resin composition is an epoxy resin composition for usein electric or electronic part;

(42) the blasting method according to item (41) above, characterized inthat the epoxy resin composition is a discarded material produced in anencapsulation step for the electric or electronic part;

(43) the blasting method according to item (41) above, characterized inthat the electric or electronic part is a semiconductor device; and

(44) the blasting method according to item (38) above, characterized inthat the inorganic filler contains 70% by weight or more of a silicacomponent.

Further, the present invention relates to:

(45) an industrial product having a surface treated with a shot materialwhich contains an epoxy resin composition and inorganic filler;

(46) a method for reprocessing waste, characterized by conducting ablasting treatment using a shot material which contains an epoxy resincomposition and inorganic filler; and

(47) a reproduced product obtained by a method for reprocessing wastecharacterized by conducting a blasting treatment using a shot materialwhich contains an epoxy resin composition and inorganic filler.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

As a shot material according to the first embodiment of the presentinvention, there can be mentioned a shot material characterized in thatit contains a styrene ion-exchange resin or/and a dried sludge-derivedmaterial. The styrene ion-exchange resin has a cross-linked structure,and hence is preferable in mechanical strength and heat resistance(which are physical properties required for peeling films), and it hasan ionic group and hence is a material having preferable antistaticeffect (which is an effect to prevent the shot material from adhering tothe materials peeled).

With respect to the type of the ionic group in the styrene ion-exchangeresin, there is no particular limitation, but, generally, it is sulfonicacid or a salt thereof, or a quaternary ammonium salt. With respect tothe amount of the ionic group introduced into the resin, there is noparticular limitation, but, generally, it is 1 to 99 mol %. The styreneion-exchange resin may be either a virgin material (which means anunused resin; this applies to the following) or a waste material whichhas been used for a purpose. The used waste material includes discardedmaterials and defectives discharged from a plant. From the viewpoint ofeffective utilization of resources and reduction of waste, it is morepreferred that a used waste material is used. The styrene ion-exchangeresin used in the present invention may be a mixture of a virginmaterial and a used waste material.

It is especially preferred that the styrene ion-exchange resin containedin the shot material of the present invention is in the form ofparticles. With respect to the form of the styrene ion-exchange resinparticles, there is no particular limitation, and the particles may havevarious forms, such as a spherical form, a long spherical form, aneedle-like form, and a scale-like form. Of these, from the viewpoint ofobtaining preferable impact resistance of the particles, uniformabrasive effect, and the like, it is preferred that part more than halfof the particles are in a spherical form or a long spherical form. Inthe present invention, the spherical form or long spherical form meansthat the projected view or plan view of the particle has a circularform, an elliptic form, an extended circular form, a peanut form, or anegg form, which is more preferred than particles having an angular orindefinite form. In the present invention, the styrene ion-exchangeresin is generally used in a state such that it is swelled with water,but the resin may be either used as it is as a shot material or used ina state of being frozen or dried as a shot material. Especially whenused in a state of being dried or frozen, more preferable blastingeffect is expected.

In the present invention, with respect to the method for formingparticles of the styrene ion-exchange resin, there is no particularlimitation, and examples include a method in which particles are formedfrom mass or pellets of the styrene ion-exchange resin using a knowncrusher or a known grinder, such as a ball mill or a grinding mill. Theparticle size of the ion-exchange resin used in the blasting treatmentis generally about 0.0001 to 10 mm, especially, more preferably about0.005 to 5 mm. Examples of methods for adjusting the particle sizeinclude a method in which the ion-exchange resin is classified before orafter drying or freezing, and a method in which the ion-exchange resinis ground by means of a grinder or the like and then classified. Astandard for the classification cannot be generally specified since itvaries depending on the use, but it is preferred that about 70% byweight or more of the total weight falls in the range of about ±20% ofthe average particle size. The classification may be either a dryprocess or a wet process.

With respect to the sludge for the dried sludge-derived materialcontained in the shot material of present invention, there is noparticular limitation, but sludge containing an inorganic component in alarge amount is desired. Examples of inorganic components include metalsalts, metal oxides, and metal hydroxides of Ca, Al, Si, Fe, Mg, Ti, Na,K, or Cu. Examples of metal salts include carbonates, halide saltsincluding hydrochlorides, sulfates, phosphates, nitrates, acetates, andborates. It is desired that the content of the inorganic component inthe dried sludge is 30% by weight or more.

The above sludge can be obtained from construction wastewater treatment,plant wastewater treatment, water treatment, or sewage treatment, but,generally, the sludge obtained from sewage treatment contains a largeamount of an organic component and therefore, it is more desired thatsludge other than this is used. Particularly, sludge discharged from afabrication plant or assembling plant of semiconductor, (liquid crystal)substrate, or cathode ray tube has a single formulation and contains alarge amount of an inorganic component and hence is more preferred asthe shot material. Generally, the sludge is dried by heating inincineration or by means of a kiln, and then buried or mixed intocement, but, in the present invention, the dried material obtained fromthe sludge is used as a shot material for use in blasting treatment. Thedried sludge-derived material used in the present invention can beobtained by a known treatment. For example, the sludge is made tocoagulate and settle naturally or by means of a chemical, such as acoagulant, or a mechanical means, such as pressing or centrifuging. Thesludge which coagulates and settles can be obtained by filtration anddrying if desired. As a method for drying the sludge containingmoisturesin addition to the above-mentioned incineration or kilntreatment, any drying method including sun-drying, freeze-drying,hot-air drying, and vacuum drying may be used.

The dried sludge-derived material may be either used as it is as a shotmaterial or adjusted to have a predetermined particle size. With respectto the particle size, there is no particular limitation, but theparticle size is generally about 0.0001 to 10 mm, more preferably about0.005 to 5 mm. As a method for adjusting the particle size of the driedsludge, the particle size may be adjusted before drying, or the driedsludge may be ground by means of a grinder, such as a ball mill or agrinding mill, and then classified. A standard for the classificationcannot be generally specified since it varies depending on the use, butit is preferred that about 70% by weight or more of the total weightfalls in the range of about ±20% of the average particle size. Theclassification may be either a dry process or a wet process.

In the shot material according to the above embodiment of the presentinvention, for obtaining satisfactory peel effect for coat film in theblasting treatment, the styrene ion-exchange resin or/and the driedsludge-derived material are contained in an amount of about 0.1% byweight or more, preferably about 1% by weight or more. When the shotmaterial and another shot material described below in detail are used incombination, it is preferred that the amount of the styrene ion-exchangeresin or/and the dried sludge-derived material falls in the above range.

The shot material according to the above embodiment of the presentinvention may contain individually the styrene ion-exchange resin andthe dried sludge-derived material or both the styrene ion-exchange resinand the dried sludge-derived material in combination.

As a shot material according to the second embodiment of the presentinvention, there can be mentioned a shot material characterized in thatit contains a resin (C) comprised of a resin (A) containing a rubbercomponent {heresinafter, frequently referred to simply as “resin (A)”}and a resin (B) containing no rubber component {heresinafter, frequentlyreferred to simply as “resin (B)”}.

With respect to the resin (A) containing a rubber component in thepresent invention, there is no particular limitation, and examplesinclude ABS (acrylonitrile/butadiene/styrene) resins, HIPS (high impactpolystyrene) resins, and alloys of the above resin and another resin.With respect to the alloy, there is no particular limitation as long asit is a resin compatible with ABS and/or HIPS, but, generally, alloys,such as ABS/PC (polycarbonate), ABS/PET (polyethylene terephthalate),ABS/PVC (polyvinyl chloride), ABS/PPE (polyphenylene ether), ABS/PSF(polysulfone), ABS/PBT (polybutylene terephthalate), ABS/nylon, andHIPS/PPE (polyphenylene ether), HIPS/PMMA (polymethyl methacrylate), andHIPS/polyolefin, are typical. In the used resin waste material in thepresent invention, these resins may be contained individually or amixture of the two or more resins may be contained. When the resin (A)containing a rubber component is contained in the shot material, thetoughness of the shot material particles is improved in the blastingtreatment, so that the amount of dust generated during the blastingtreatment is reduced.

With respect to the resin (B) containing no rubber component in thepresent invention, there is no particular limitation, and examplesinclude AS, PS, PC, PET, PVC, PPE, PSF, PBT, nylon, PMMA, andpolyolefin. Of these, preferred are AS and PS. When the resin (B)containing no rubber component is contained in the shot material, thehardness of the shot material becomes appropriate, so that a deposit,such as a coating, can be efficiently removed without causing no oralmost no damage on the surface of a material to be blasted (e.g., aresin product).

Each of the above-mentioned resin (A) containing a rubber component andresin (B) containing no rubber component can be easily produced, andones commercially available for various grades, such as general-purpose,high-stiffness, high-impact, wear-resistance, high-sliding,heat-resistance, transparence, high-luster, chemical-resistance, andcoating grades, may be used. Alternatively, the resins may be ones whichare not commercially available but produced in a resin plant. The resins(A) and (B) may contain various additives for resin, such as anantistatic agent, a coloring agent, a pigment, an antioxidant, a flameretardant, a plasticizer, a light resistance accelerator, acompatibilizer, a surface treating agent, a modifier, a coloring agent(e.g., carbon black), glass fiber, paper, and nonwoven fabric.

As the resin (C) comprised of the resin (A) containing a rubbercomponent and the resin (B) containing no rubber component, either theresins may be mixed together or a mixture of the resins may be used.Specifically, in the resin (C), either the resin (A) and the resin (B)may be individually in an independent form (particles, pellets, ormass), or the resin (A) and the resin (B) may be mixed with each otherin a molten state. When using a virgin material (which means an unusedresin; this applies to the following), these resins are mixed and can beused as a shot material. When using a used waste material, either resinsseparately salvaged may be mixed together or a mixture of the resins maybe used. As the used resin salvaged from used waste materials, all kindsof resin waste materials which have been used in electrical appliances,office appliances, vehicles, and miscellaneous goods can be used. As theused resin, ones discharged in a fabrication plant as discardedmaterials of runner materials and raw material pellets may be used. Theused resins generated in a plant and those salvaged from thestandardized products (which are the same product or belong to the sameproduct group) generally have consistent physical properties, andtherefore they are more preferred from the viewpoint of reuse. Examplesof the standardized products include recording media related products(videocassette shell), more specifically, videocassette for professionaluse and 8 mm videocassette and DV cassette for consumer use, householdgame machine (controller), and portable phone. Especially, in thepresent invention, it is preferred that the resin (C) is a used resinsalvaged from a used magnetic recording product. With respect to themagnetic recording product, there is no particular limitation, andexamples include the above-mentioned videocassettes and music tapecassettes. The magnetic recording product includes not only a magneticrecording medium but also a housing for protecting it, such as a casingand a shell.

In these products, generally, for improving the impact resistance of theproducts, the resin (A) containing a rubber component is used. On theother hand, the resin (B) containing no rubber component, such as a PSor AS resin, is frequently used as a window material or a casingmaterial (transparent) in the products. When the used resins are surelyseparated from one another, the individual resins salvaged {the resin(A) and the resin (B)} are mixed together and can be used as a shotmaterial, but, when the resin (A) and the resin (B) are contained mixedin a product, such as a cassette casing, both the resins are containedin the resin salvaged. In this case, it is preferred that the weightratio of the resin (B) to the resin (A) {(B)/(A)} is in the range ofabout 0.001 to 5. When the weight ratio is not in the above range, it ispreferred to make up for a lack of the resin (A) or resin (B) so thatthe weight ratio of the resin (B) to the resin (A) falls within theabove range. When the individual resins (which may be used resins) aremixed together and used, it is more preferred that the resins are mixedin the above ratio and used as a shot material. It is more preferredthat the content of the resin (C) comprised of the resin (A) and theresin (B) in the shot material is about 0.1 to 100% by weight. Forsuppressing the amount of dust generated during the blasting treatmentand preventing the blasted surface from suffering a damage, it ispreferred that the resin (C) content falls in the above range. The resin(C) content is similar when another shot material described below indetail is contained.

It is especially preferred that the resin (A), the resin (B), or a mixedresin of the resin (A) and the resin (B) contained in the shot materialof the present invention is in the form of particles. With respect tothe form of the particles, there is no particular limitation, and theparticles may have various forms, such as a spherical form, a longspherical form, a needle-like form, and a scale-like form. Of these,from the viewpoint of obtaining preferable impact resistance of theparticles, uniform abrasive effect, and the like, it is preferred thatpart more than half of the particles a resin a spherical form or a longspherical form. In the present invention, the spherical form or longspherical form means that the perspective view or plan view of theparticle has a circular form, an elliptic form, an extended circularform, a peanut form, or an egg form, which is more preferred thanparticles having an angular or indefinite form. With respect to theparticle size of the particles, there is no particular limitation, butthe particle size is generally about 0.0001 to 10 mm, more preferablyabout 0.005 to 5 mm.

With respect to the method for forming the particles, there is noparticular limitation, and examples include a method in which particlesare formed from mass or pellets of the resin using a known crusher or aknown grinder, such as a ball mill or a grinding mill. The resin (A),the resin (B), or a mixed resin of the resin (A) and the resin (B) maybe either ground by means of a grinder and then used as a shot material,or ground and then classified into a predetermined particle size andused. A standard for the classification cannot be generally specifiedsince it varies depending on the use, but it is preferred that about 70%by weight or more of the total weight falls in the range of about ±20%of the average particle size. The classification may be either a dryprocess or a wet process.

Further as a shot material according to the third embodiment of thepresent invention, there can be mentioned a shot material characterizedin that it contains an epoxy resin composition and inorganic. As theepoxy resin used as the shot material in the present invention,preferred are compounds having two or more epoxy groups, including epoxyresins used in applications of electric use, coating, civil engineering,adhesive, and composite material, and there is no particular limitation.Of these, more preferred are those used as epoxy resins for electric useand composite material. Among the epoxy resins for electric use andcomposite material, more preferred are epoxy resins used in ICencapsulation materials and printed boards. The epoxy resin may be anytype, such as bisphenol A type, brominated bisphenol A type, phenolicnovolak type, cresol novolak type, alicyclic type, heterocyclic type,and flexible epoxy, but, especially, more preferred are cresol novolaktype and phenolic novolak type epoxy resins.

In the epoxy resin, generally, as a curing agent, one having two or morefunctional groups for curing the epoxy resin is used. The epoxy resincomposition used in the present invention may contain a curing agent aswell as the above epoxy resin. As examples of curing agents, there canbe mentioned phenolic compounds and amine compounds. In addition to thecuring agent, an additive, such as a surface treating agent, a curingcatalyst, a flame retardant (e.g., a halogen compound or a phosphoruscompound), a flame retardant auxiliary (e.g., an antimony compound or anitrogen compound), a coloring agent, an ion-capturing agent, anelastomer, or a wax, may be contained in the epoxy resin composition. Aspreferred examples of the epoxy resin compositions used in the presentinvention, there can be mentioned epoxy resin compositions for use inelectric or electronic part. Especially, as the epoxy resin compositionused in the present invention, more preferred are discarded materialsproduced in an encapsulation step for the electric or electronic part.

With respect to the inorganic filler used in the shot material accordingto the above embodiment of the present invention, there is no particularlimitation, and examples include crystalline silica, fused silica,calcium carbonate, magnesium carbonate, alumina, magnesia, talc, clay,calcium silicate, titanium oxide, asbestos, glass fiber, calciumfluoride, calcium sulfate, and calcium phosphate. In the presentinvention, a plurality of these inorganic filler may be used incombination. Of these, more preferred is inorganic filler comprisedmainly of silica. In the inorganic filler comprised mainly of silica, itis more preferred that the inorganic filler contains about 70% by weightor more of a silica component. The inorganic filler may be contained inan amount about 1 to 20 times, preferably about 2 to 5 times the weightof the epoxy resin.

The above-described epoxy resin and inorganic filler may be presenteither independently or in the form of a composite material containingboth the epoxy resin and the inorganic filler, such as an encapsulationmaterial for electric or electronic part, or an epoxy substratematerial. In the former, generally, the epoxy resin and the inorganicfiller are mixed together by a known method to form the shot material ofthe present invention. In the latter, either the composite material maybe used as it is as a shot material, or the epoxy resin or inorganicfiller may be further added to the composite material. In the shotmaterial of the present invention, a discarded material (e.g., a runnermaterial, a non-standardized product, mold flash or the like) dischargedin a plant may be used, or a used waste material salvaged from themarket (e.g., an IC chip, a printed board or the like) may be used. Fromthe viewpoint of effective utilization of resources and reduction ofwaste, it is more preferred to use a used waste material or a discardedmaterial generated in a plant.

It is especially preferred that the epoxy resin, the inorganic filler,or a mixture of the epoxy resin and the inorganic filler contained inthe shot material of the present invention is in the form of particles.With respect to the form of the particles, there is no particularlimitation, and the particles may have various forms, such as aspherical form, a long spherical form, a needle-like form, and ascale-like form. Of these, from the viewpoint of obtaining preferableimpact resistance of the particles, uniform abrasive effect, and thelike, it is preferred that part more than half of the particles a resina spherical form or a long spherical form. In the present invention, thespherical form or long spherical form is as defined above. When theepoxy resin, the inorganic filler, or the mixture of the epoxy resin andthe inorganic filler is in the form of particles, with respect to theparticle size of the particles, there is no particular limitation, butthe particle size is generally about 0.0001 to 10 mm, generally, morepreferably about 0.005 to 5 mm. With respect to the method for formingparticles of the epoxy resin, the inorganic filler, or the mixture ofthe epoxy resin and the inorganic filler, there is no particularlimitation, and examples include the above-mentioned methods for formingparticles, such as a method in which particles are formed from mass orpellets of the resin, or a used waste material or a discarded materialgenerated in a plant using a known crusher or a known grinder, such as aball mill or a grinding mill.

In the present invention, the above-described (a) shot materialcontaining a styrene ion-exchange resin or a waste material causedtherefrom, or/and a dried sludge-derived material, (b) shot materialcontaining a resin (C) which is comprised of a resin (A) containing arubber component and a resin (B) containing no rubber component, and (c)shot material containing an epoxy resin composition and inorganic fillermay be used individually or in combination. Further, another shotmaterial may be mixed into each of the shot materials (a) to (c) or thecombination of these shot materials. As the another shot material, aconventional shot material may be used, and examples include organicpolymer shot materials and inorganic (metal, ceramic) shot materials.

Examples of organic polymer shot materials include melamine resins, urearesins, phenolic resins, ketone resins, epoxy resins, guanamine resins,urea resins, unsaturated polyester resins, polycarbonate resins, acrylicresins, polyamide resins, polyphenolic resins, polyester resins,polystyrene resins, ABS (acrylonitrile-butadiene-styrene) resins, AS(acrylonitrile-styrene) resins, PAN (polyacrylonitrile) resins, POM(polyacetal) resins, PPE (polyphenylene ether), PEO (polyethyleneoxide), AES {acrylonitrile-(ethylene-propylene rubber)-styrene}, AAS(acrylonitrile-acrylate-styrene), EVA (ethylene-vinyl acetatecopolymer), butadiene resins, vinyl acetate resins, methacrylic resins,polysulfone resins, cellulose, polyurethane resins, biodegradable resins(such as chitin, chitosan, polylactic acid, polyvinyl alcohol, andpolyamino acid), polyacrylamide, polycarboxylate ester, polyaminoethylacrylate salts, and sodium polystyrenesulfonate. The organic polymershot material may be either a virgin material or a waste material whichhas been used for a purpose. Especially, from the viewpoint of effectiveutilization of resources and reduction of waste, it is more preferred touse a blend of the organic polymer shot material comprised of a usedwaste material as a raw material and the shot material of the presentinvention.

Examples of inorganic (metal, ceramic) shot materials include steelparticles, zinc particles, aluminum particles, alumina, silica, mica,carbon black, calcium carbonate, glass (fiber, balloon), titanium oxide,magnesium carbonate, talc, clay, and a variety of metal oxides, metalhydroxides, and metal salts. The inorganic shot material may be either avirgin material or a waste material which has been used for a purpose.Especially, from the viewpoint of effective utilization of resources andreduction of waste, it is more preferred to use a blend of the inorganicshot material comprised of a used waste material as a raw material andthe shot material of the present invention.

In the present invention, by selecting or controlling the content of theshot material of the above three embodiments or the type or content ofanother shot material incorporated, the specific gravity, hardness andthe like of the shot material can be appropriately selected orcontrolled depending on the form of the material to be blasted or thepurpose of the blasting treatment. For example, the use of alumina,silica, or glass fiber having a high hardness as another shot materialis preferred in a relatively hard blasting treatment. On the other hand,the use of, for example, calcium carbonate, magnesium carbonate, talc,or clay having a low hardness as another shot material is preferred in arelatively soft blasting treatment. The use of glass balloon ispreferred when lowering the specific gravity of the shot material. Whencarbon black is incorporated, conductivity can be imparted to the shotmaterial, making it possible to more effectively prevent the shotmaterial from being charged. Incorporation of an organic shot materialcan advantageously improve the shot material in toughness.

The shot material of the present invention may contain a known additive.For example, when iron oxide in a spherical form, a shattered form, or afibrous form or a compound containing iron oxide (e.g., ferrite) isincorporated, the shot material can be prevented from beingelectrostatically charged during the grinding step for granulation ofthe shot material or during the blasting. When a pigment containing ironoxide or a compound containing iron oxide (e.g., ferrite), specifically,α FeOOH, β FeOOH, γ FeOOH, α Fe₂O₃, γ Fe₂O₃, Fe₃O₄, MoFe₂O₃, Mo₆Fe₂O₃,or the like is incorporated, the shot material can be colored andidentified by color, leading to an advantage in handling or control ofthe products.

With respect to the amount of the additive incorporated, there is noparticular limitation, and it cannot be generally specified since itvaries depending on the type or purpose of use of the additive. Forexample, when the above-mentioned pigment containing iron oxide or acompound containing iron oxide (e.g., ferrite) is incorporated as anadditive, the amount of the pigment incorporated varies depending on thepurpose of incorporation, but it is preferably about 10% by weight orless, especially preferably about 0.001 to 1% by weight.

The present invention provides a blasting method using theabove-described novel shot material. With respect to the blastingmethod, there is no particular limitation, and, for example, an impellerhaving a plurality of rectangular plates radially provided on a rotaryshaft is rotated at a high speed to achieve centrifugal shot of the shotmaterial of the present invention, or the shot material of the presentinvention is shot by an air nozzle using compressed air. In shot of theshot material of the present invention, a medium, such as water or air,may be either used or not used. It is especially preferred that the shotmaterial of the present invention is shot using gas as a medium.

As a preferred embodiment of the blasting method of the presentinvention, there can be mentioned a method in which the shot material ofthe present invention is sprayed, together with a gas stream. As theabove method, various types of blasting methods can be used, but a dryblasting method is more preferred. Examples of dry blasting methodsinclude: (1) a gravity blasting method in which powder is placed in atank at a position higher than a nozzle, and the powder which falls bygravity toward a discharge outlet formed in the bottom of the tank isshot through the nozzle, together with compressed gas; (2) a directblasting method in which a powder pressure feed tank is packed withpowder and compressed gas is fed into the tank, and the powderdischarged from a discharge outlet formed in the bottom of the tank isshot through a nozzle, together with the compressed gas; and (3) asiphon blasting method in which powder is placed in a tank at a positionlower than a nozzle, and the powder discharged by suction of compressedgas from a discharge outlet formed in the bottom of the tank is shotthrough the nozzle, together with the compressed gas, and any of theseblasting methods can be used.

In the above methods, as compressed gas, generally, compressed air isused but, for avoiding dust explosion, inert gas, such as nitrogen, maybe used. In the blasting treatment, the powder amount, the pressure ofcompressed gas, and the shot speed and time can be appropriatelyselected according to the type of the powder used or the type or depositstate of the material to be peeled (coat film).

When conducting the above-mentioned blasting treatment, the temperatureof an object to be treated may be room temperature, but it is preferredthat the object to be treated is preheated. The heating temperaturecannot be generally specified since it varies depending on the type ofthe object to be treated, but it is preferred to set the heatingtemperature at such a high temperature that the quality of the object tobe treated does not deteriorate.

The shot material of the present invention which has been used in theblasting treatment can be recovered and separated from depositsubstances using a conventional after-treatment equipment, such as acyclone, and reused. The shot material having deposit substances mixedcan be either reused as a shot material by incineration treatment orblended with cement and buried. From the viewpoint of effectiveutilization of resources, it is more preferred that the used shotmaterial is reused as a shot material after incineration or blended withcement.

The blasting method of the present invention can be used in a variety ofapplications. For example, the blasting method of the present inventionis advantageously used for removing a coating. With respect to thecoating, there is no particular limitation, and examples include a vinylchloride coating, an urethane coating, and an acryl coating. Withrespect to the coated article, there is no particular limitation, andexamples include resin shaped articles and wooden articles. With respectto the resin shaped article, there is no particular limitation, andexamples include a bumper, an instrument panel or a dashboard ofautomobile, or a pleasure boat. In addition, the blasting method of thepresent invention can be used for peeling a coating, such as a whiteline on the pavement. The blasting method of the present invention canbe used for deburring of a metal cast article or a resin shaped articleor for cleaning and polishing surface. Further, the blasting method ofthe present invention can be used for removing deposits, removing adeposit to a rubber mold, or removing pollutant, rust, or surface oxide.

Heresinbelow, the present invention will be described in more detailwith reference to the following Examples, which should not be construedas limiting the scope of the present invention.

EXAMPLE 1

Using as a shot material a dried material (particle size after grindingtreatment: 500 to 850 μm) formed from a cation-exchange resin dischargedfrom a liquid crystal plant, a used CD film (acryl-coated Al film) wassubjected to peel treatment by means of a direct-pressure sandblastingmachine for 10 seconds, and the surface state (peel area) was measured.

EXAMPLE 2

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a dried material (particle sizeafter grinding treatment: 500 to 850 μm) formed from an anion-exchangeresin discharged from a semiconductor plant was used as a shot material.

EXAMPLE 3

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a dried material formed from acommercially available cation-exchange resin (Amberlite IR124Na;particle size after grinding treatment: 500 to 850 μm) was used as ashot material.

EXAMPLE 4

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a dried material formed from acommercially available anion-exchange resin (Amberlite IRA402BL;particle size after grinding treatment: 500 to 850 μm) was used.

EXAMPLE 5

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a commercially available resinshot material (melamine-based; particle size: 500 to 850 μm) was blendedin an amount of 60% with the dried cation-exchange resin material inExample 1.

EXAMPLE 6

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a commercially available resinshot material (nylon-based; particle size: 500 to 850 μm) was blended inan amount of 20% with the dried anion-exchange resin material in Example4.

EXAMPLE 7

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that a used ABS resin (cell wastefrom 8 mm videocassette; particle size: 500 to 850 μm) was blended in anamount of 30% with the dried cation-exchange resin material in Example1.

COMPARATIVE EXAMPLE 1

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that the commercially available resinshot material used in Example 5 was solely used.

COMPARATIVE EXAMPLE 2

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 1 except that the commercially available resinshot material used in Example 6 was solely used.

The results of the above examples were compared and studied. As aresult, it has been found that, in Comparative Examples 1 and 2, thepeel area per unit period of time for the treatment is small and theamount of fine powder scattered is large, as compared to those inExamples 1 to 7. Further, it has been confirmed that, by blending theshot material of the present invention with a commercially availableshot material or used resin waste, the peel effect is improved.

EXAMPLE 8

Using as a shot material a dried sludge-derived material (containing Al:30% by weight, Ca: 25% by weight, and O: 35% by weight; particle size:500 to 850 μm) discharged from a liquid crystal plant, a used CD film(acryl-coated Al film) was subjected to peel treatment by means of adirect-pressure sandblasting machine for 10 seconds, and the surfacestate (peel area) was measured.

EXAMPLE 9

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a dried sludge-derived material(containing Ca: 50% by weight, O: 10% by weight, and F: 20% by weight)discharged from a cathode ray tube plant was used as a shot material.

EXAMPLE 10

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a dried sludge-derived material(containing Si: 30% by weight, O: 35% by weight, Al: 15% by weight, andCa: 10% by weight) discharged from a semiconductor plant was used as ashot material.

EXAMPLE 11

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a commercially available resinshot material (melamine-based; particle size: 500 to 850 μm) was blendedin an amount of 70% with the dried sludge-derived material in Example 8.

EXAMPLE 12

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a commercially available resinshot material (nylon-based; particle size: 500 to 850 μm) was blended inan amount of 20% with the dried sludge-derived material in Example 9.

EXAMPLE 13

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a dried material (particle size:500 to 850 μm) formed from a used ion-exchange resin was blended in anamount of 80% with the dried sludge-derived material in Example 10.

EXAMPLE 14

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that a used ABS resin (cell wastefrom 8 mm videocassette; particle size: 500 to 850 μm) was blended in anamount of 30% with the dried sludge-derived material in Example 8.

COMPARATIVE EXAMPLE 3

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that the commercially available resinshot material used in Example 11 was solely used.

COMPARATIVE EXAMPLE 4

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 8 except that the commercially available resinshot material used in Example 12 was solely used.

The results of the above examples were compared and studied. As aresult, it has been found that, in Comparative Examples 3 and 4, thepeel area per unit period of time for the treatment is small and theamount of fine powder scattered is large, as compared to those inExamples 8 to 14. Further, it has been confirmed that, by blending theshot material of the present invention with a commercially availableshot material or used resin waste, the peel effect is improved.

In the following Examples 15 to 20 and Comparative Examples 5 and 6,individually using the samples shown below as a shot material, a used CD(acryl-coated Al film) was subjected to peel treatment for 10 seconds,and the surface state (peel area) was measured.

EXAMPLE 15

A resin salvaged from cassette cell for business purposes (materialsalvaged from a broadcasting station):

a mixture of: a shell body (top and bottom); ABS resin (95% by weight;high-flow high-stiffness grade) and a window of the shell (transparentportion); AS resin (5% by weight); which was ground and classified sothat the particle size became 500 to 850 μm.

EXAMPLE 16

A mixture of an ABS resin (70% by weight; 500 to 850 μm) and an AS resin(30% by weight; 500 to 850 μm), which was obtained by classifying theresin pellet waste discharged from a resin molding plant.

EXAMPLE 17

A resin salvaged from VHS cassette cell:

a mixture of: a shell body (top and bottom); HIPS resin (97% by weight;high-flow high-stiffness grade) and a window (transparent) portion ofthe shell; PS resin (3% by weight); which was ground by means of agrinder so that the particle size became 500 to 850 μm.

EXAMPLE 18

A mixture of virgin resins:

a mixture of a ground/classified general-purpose high-impact grade ABSresin (40% by weight; 500 to 850 μm) and a ground/classifiedgeneral-purpose GPPS resin (60% by weight; 500 to 850 μm).

EXAMPLE 19

The resin in Example 15 added 80% by weight of a commercially availableresin shot material (melamine-based; particle size: 500 to 850 μm).

EXAMPLE 20

The resin in Example 17 added 60% by weight of a commercially availableresin shot material (nylon-based; particle size: 500 to 850 μm).

COMPARATIVE EXAMPLE 5

The commercially available resin shot material used in Example 19.

COMPARATIVE EXAMPLE 6

The commercially available resin shot material used in Example 20.

The results of the above examples were compared and studied. As aresult, it has been found that, in Comparative Examples 5 and 6, thepeel area per unit period of time for the treatment is small and theamount of fine powder scattered is large, as compared to those inExamples 15 to 20. Further, it has been confirmed that, by blending theshot material of the present invention with a commercially availableshot material, the peel effect is further improved.

EXAMPLE 21

A runner material for IC encapsulation material (epoxy resin content:10% by weight; silica content: 80% by weight) discharged from asemiconductor assembling plant was ground and classified so that theparticle size became 500 to 850 μm. Using the resultant material as ashot material, a used CD film (acryl-coated Al film) was subjected topeel treatment by means of a direct-pressure sandblasting machine for 10seconds, and the surface state (peel area) was measured.

EXAMPLE 22

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 21 except that 60% by weight of sphericalsilica was added to 40% by weight of a glass epoxy substrate and theresultant blend was mixed, ground, and classified so that the particlesize became 500 to 850 μm.

EXAMPLE 23

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 21 except that a commercially available resinshot material (melamine-based; particle size: 500 to 850 μm) was blendedin an amount of 50% with the shot material in Example 21.

EXAMPLE 24

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 21 except that a commercially available resinshot material (nylon-based; particle size: 500 to 850 μm) was blended inan amount of 30% with the shot material in Example 22.

COMPARATIVE EXAMPLE 7

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 21 except that the commercially availableresin shot material used in Example 23 was solely used.

COMPARATIVE EXAMPLE 8

A used CD film was subjected to blasting treatment in substantially thesame manner as in Example 21 except that the commercially availableresin shot material used in Example 24 was solely used.

The results of the above examples were compared and studied. As aresult, it has been found that, in Comparative Examples 7 and 8, thepeel area per unit period of time for the treatment is small and theamount of fine powder scattered is large, as compared to those inExamples 21 to 24. Further, it has been confirmed that, by blending theshot material of the present invention with a commercially availableshot material or used resin waste, the peel effect is improved.

INDUSTRIAL APPLICABILITY

According to the present invention, ion-exchange resin waste or sludgedischarged from a plant, which has conventionally not been effectivelyutilized, can be reused. In addition, the used resin (C), which iscomprised of the resin (A) containing a rubber component and the resin(B) containing no rubber component, can be utilized. Further, a mixtureof an epoxy resin composition and inorganic filler, typically a usedencapsulation material, which has conventionally not been effectivelyutilized, can be reused. Thus, by the present invention, effectiveutilization of resources can be achieved and waste is reduced. Further,the use of the shot material of the present invention improves theblasting treatment. That is, the present invention not only improves theblasting treatment in working efficiency but also significantlycontributes to protection of the environment.

1. A blasting treatment method comprising at least the step of blastingshot material comprising a resin (C) comprised of a resin (A) containinga rubber component and a resin (B) containing no rubber component. 2.The blasting treatment method according to claim 1, wherein at least oneof said resin (A) containing a rubber component and said resin (B)containing no rubber component is a used resin.
 3. A blasting method ofclaim 1, wherein said resin (C) is a used resin salvaged from a usedmagnetic recording product.
 4. The blasting method according to claim 1,wherein the weight ratio of said resin (B) containing no rubbercomponent to said resin (A) containing a rubber component {(B)/(A)} isin the range of 0.001 to
 5. 5. The blasting method according to claim 1,wherein the content of said resin (C) in said shot material is 0.1 to100% by weight.
 6. The blasting method according to claim 1, whereinsaid resin (A) containing a rubber component is a HIPS (high impactpolystyrene) and/or ABS (acrylonitrile/butadiene/styrene resin), andsaid resin (B) containing no rubber component is a PS (polystyrene)and/or AS (acrylonitrile/styrene resin).
 7. A shot material comprising aresin (C) comprised of a resin (A) containing a rubber component and aresin (B) containing no rubber component.
 8. The shot material accordingto claim 7, wherein at least one of said resin (A) containing a rubbercomponent and said resin (B) containing no rubber component is a usedresin.
 9. The shot material according to claim 7, wherein said resin (C)is a used resin salvaged from a used magnetic recording product.
 10. Theshot material according to claim 7, wherein the weight ratio of saidresin (B) containing no rubber component to said resin (A) containing arubber component {(B)/(A)} is in the range of 0.001 to
 5. 11. The shotmaterial according to claim 7, wherein the content of said resin (C) insaid shot material is 0.1 to 100% by weight.
 12. The shot materialaccording to claim 7, wherein said resin (A) containing a rubbercomponent is a HIPS (high impact polystyrene) and/or ABS(acrylonitrile/butadiene/styrene resin), and said resin (B) containingno rubber component is a PS (polystyrene) and/or AS(acrylonitrile/styrene resin).
 13. An industrial product having asurface resulting from blasting with shot material comprising a resin(C) comprised of a resin (A) containing a rubber component and a resin(B) containing no rubber component.
 14. A method of processing a wastematerial at least comprising the step of blasting the waste materialwith shot material comprising a resin (C) comprised of a resin (A)containing a rubber component and a resin (B) containing no rubbercomponent.
 15. A product obtained by a blasting a waste product withshot material comprising a resin (C) comprised of a resin (A) containinga rubber component and a resin (B) containing no rubber component.